Sino-German cooperation. Before 1937, Germany and German corporations invested a great deal of money into developing China, and military advisors spent a great deal of time with the armies of the Republic. In fact at the battle of Shanghai, the stiffest resistence to the Japanese came from German-trained and -equipped units. The Republic's pro-West and anti-Communist leanings showed great promise to the Nazi government. It shouldn't come as a surprise that some have called Kai-Shek a fascist.
Chiang Wei-Ko, adopted son of the President, served in the Wehrmacht primarily as a political stunt, but during his service he apparently excelled in alpine ranging, marksmanship, the study of combined-arms military tactics, and even participated in the annexation of Austria. He worked his way up to a commission to Leutnant and was about to take part in the invasion of Poland, but was recalled to China. His career from then on was with Kuomingtang forces until their exile to Taiwan.